OBJECTIVE: To determine the feasibility of inducing miosis and ciliary muscle contraction in enucleated monkey eyes by electrical stimulation RESULTS We developed a preparation in which electrical stimulation of freshly enucleated monkey (rhesus) eyes produces iris muscle function for up to 36 hours after enucleation. Pupil constriction or pupil dilation was induced in these eyes using electrical stimulation of nerve endings via a suction electode. Real-time video imaging in conjunction with the electrical stimulation allowed analysis of the dynamics of the iris muscle function. Maximal iris responses were obtained with pulses of 70ms intervals and 100ms duration. The extent and time course of the pupil function were similar to the pupillary light reflex in living monkeys. Pharmacological treatment of the preparation with specific cholinergic agonists and antagonists provided information on the specific mechanism of nervous control of pupil constriction and pupil dilation. Ciliary body movement or lens thickening, indicative of ciliary muscle function, was not seen. This preparation provides a useful tool for studying the normal neuronal control of pupillary muscle function and the effect of various pharmacological agents, independent of the confounding neurohumoral influences present in the living animal. FUTURE DIRECTIONS We plan to further develop this model by maintaining ocular circulation in an attempt to achieve ciliary body movement or lens thickening during stimulation. KEY WORDS pupil, orbitotomy